气候变化领域集成服务门户(CCPortal): Extricating dynamic topography from subsidence patterns: Examples from Eastern North America's passive margin

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DOI	10.1016/j.epsl.2019.115840
	Extricating dynamic topography from subsidence patterns: Examples from Eastern North America's passive margin
	Morris M.; Fernandes V.M.; Roberts G.G.
发表日期	2020
ISSN	0012821X
卷号	530
英文摘要	Global sea-level (eustatic) histories generated by backstripping stratigraphy are predicated upon the lithosphere having a well understood tectonic history. However, sub-plate processes play a role in governing lithospheric vertical motions with timescales and amplitudes akin to eustasy, which are difficult to predict. We examine how stratigraphic and geophysical observations combined with simple isostatic models can be used to disentangle histories of sub-plate support and eustasy. We focus on the passive margin of Eastern North America, where a generally accepted history of eustasy has been estimated. Negative long wavelength free-air gravity anomalies, residual ocean-age depth estimates, fast upper mantle shear wave velocities, and geodynamic models suggest that Cenozoic evolution of this passive margin has been influenced by upper mantle drawdown. We build on existing analyses to backstrip sixteen wells, which, combined with seismic data, constrain timing and extent of Cenozoic subsidence. Results indicate up to ∼1000 m of water-loaded subsidence between ∼20–0 Ma centered on the Baltimore Canyon Trough. Seismic data from the trough shows Neogene aggrading clinoforms. There is little evidence for faulting or stratigraphic growth, which indicates that Neogene lithospheric strain rates were low. Amplitude and spatial extent of Neogene subsidence are difficult to explain by glacio-eustasy or glacio-isostatic adjustment. Instead, sub-plate support calculated from conversion of shear wave velocities to temperature and isostatic calculations indicate that upper mantle drawdown was responsible for subsidence of the margin. Because mantle convection is vigorous such observations are expected throughout the stratigraphic archive. © 2019
关键词	eustasy mantle convection Neogene New Jersey margin sea level subsidence
英文关键词	Geodynamics; Geophysical prospecting; Sea level; Seismic response; Seismic waves; Shear flow; Shear waves; Strain rate; Stratigraphy; Structural geology; Topography; Water levels; Dynamic topography; Eastern north america; Eustasy; Geophysical observations; Mantle convection; Neo genes; New Jersey; Shear wave velocity; Subsidence; eustacy; mantle convection; Neogene; passive margin; S-wave; sea level; subsidence; tectonic evolution; tectonic setting; topography; Atlantic Ocean; Baltimore Canyon
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202798
作者单位	Department of Earth Science and Engineering, Imperial College London, South Kensington CampusSW7 2AZ, United Kingdom
推荐引用方式 GB/T 7714	Morris M.,Fernandes V.M.,Roberts G.G.. Extricating dynamic topography from subsidence patterns: Examples from Eastern North America's passive margin[J],2020,530.
APA	Morris M.,Fernandes V.M.,&Roberts G.G..(2020).Extricating dynamic topography from subsidence patterns: Examples from Eastern North America's passive margin.Earth and Planetary Science Letters,530.
MLA	Morris M.,et al."Extricating dynamic topography from subsidence patterns: Examples from Eastern North America's passive margin".Earth and Planetary Science Letters 530(2020).